• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.7-10
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• 2001

Adsorption of the pesticides (phosphamidon, fenitrothion, triadimefon and diniconazole) in natural zeolite (CL $I_{N}$) and several synthetic zeolites was incestigated. The pesticides were not adsorbed on zeolites (Na-Pl, SOD, ANA, JBW and CAN) synthesized from Jeju scoria. The distribution coefficient ( $K_{D}$) and the Freundlich constant ( $K_{F}$) decreased in the following sequences. FC $C_{W}$ (waste catalytic cracking catalyst)>FA $U_{F}$ (FAU Synthesized from coal fly ash)>(FAU+Na-Pl)$_{SF}$ (the mixture of FAU and Na-Pl synthesized from the ratio of Jeju scoria 6 to coal fly ash 4 by weight)>CL $I_{N}$ among the zeolites; diniconazole>fenitrothion> triadimefon>phosphamidon. As the temperature was increased, the amount of pesticide adsorbed per unit mass of zeolite increased for FC $C_{W}$, FA $U_{F}$ and (FAU+Na-Pl)$_{SF}$ but it decreased for CL $I_{N}$, for all the pesticides used in this study. It was independent of pH for phosphamidon, fenitrothion and triadimefon, but decresed as pH was increased for all the zeolites used in this study.y.udy.y.y.y.y.y.y.

• Journal of Environmental Science International
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• v.24 no.4
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• pp.505-514
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• 2015

The grid-based water balance of watershed scale was assessed in the mountainous area of Pyosun catchment in Jeju Island after analyzing precipitation, evapotranspiration, and runoff from January 2008 to December 2013. The existing results of direct runoff, evapotranspirtion, and groundwater recharge comparing to precipitation were presented 22.0%, 25.6%, and 52.4%, respectively, in Pyosun catchment. However, this study indicated each component shows 14.5%, 24.2%, and 61.0%, respectively, in the mountainous area of Pyosun catchment. Therefore, groundwater recharge rate in the mountainous area appears higher than 10% comparing to the overall catchment. It would be analyzed that the amount of direct runoff is relatively small. Moreover, this difference could be generated because of the spatial discontinuities in the process of estimating the total amount of precipitation in the mountainous area. Therefore, the grid-based spatial analysis to maximize the spatial continuity would be useful for providing a more reasonable result when the total amount of water resources are evaluated in mountainous areas in the future.

• Journal of Soil and Groundwater Environment
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• v.9 no.3
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• pp.56-61
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• 2004

The topographic variables, which influence the precipitation phenomena, are classified by elevation (ELEV), slope (SLOPE), distance to sea (SEA), obstruction (OBST), barrier (BAR), roughness (SHIELD), extracted and analysed according to resolutions. This study is performed through 100 m, 200 m, 400 m, 600 m, 800 m and 1,000 m based on 50 m DTM using TOVA (Topographic Variables Extraction Program). The result of a case study on Jeju weather station says that the variance according to resolution is generally less than that according to cardinal direction, but particularly SHIELD values and some cases for 600m resolution have a significant results.

• Journal of Environmental Science International
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• v.22 no.5
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• pp.523-531
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• 2013

In this study, a method of simulating ephemeral stream runoff characteristics in Jeju watershed is newly suggested. The process based conceptual-physical scheme is established based on the SWAT-K and applied to Cheonmi-cheon watershed which shows the typical pattern of ephemeral stream runoff characteristics. For the proper simulation of this runoff, the intermediate flow and baseflow are controlled to make downward percolation should be dominant. The result showed that surface runoff simulated by using the modified scheme showed good agreement with observed runoff data. In addition, it was found that the estimated runoff directly affected the groundwater recharge rate. This conceptual model should be continuously progressed including rainfall interception, spatially estimated evapotranspiration and so forth for the reasonable simulation of the hydrologic characteristics in Jeju island.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1409-1420
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• 2014

In this work, we have carried out a sensitivity analysis of hydrogeologic parameters such as reaction factor and drainable pore space in groundwater table fluctuation model and have found characteristics of parameter distribution according to the altitude. We found that drainable pore space which is hydrogeologic parameter of aquifer didn't show any trend with altitude while reaction factor which is groundwater flow characteristic showed clear trend with altitude. To find a sensitivity of parameters, we compared RMSE of estimated groundwater recharges by using the mean value and linear relationship of parameters. As results, the linear equation derived for entire watersheds could be applied to estimate parameters for ungauged watershed. Furthermore, the features of parameter distribution can be used to predict hydrogeologic parameter in ungauged watersheds and it is expected that those features could be used for a basic data for groundwater modeling.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.517-526
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• 2018

As groundwater recharge shows the heterogeneity in space and time due to land use and soil types, estimating daily recharge by integrated hydrologic analysis is needed. In this work, the SWAT-MODFLOW model was applied to compute daily based groundwater recharge in Jangseong region. The accuracy of the model was evaluated by comparing the observed and calculated values of the unsteady groundwater flow levels after calibrating the observed and calculated flow rates of the stream for a hydrological analysis. The estimated hydrologic components showed a strong correlation with each other and significant spatial variations regarding the groundwater recharge rate in accordance with the heterogeneous watershed characteristics such as subbasin slope, land use, and soil type. Overall, it was concluded that the coupled hydrologic models were capable of simulating the spatial variation with respect to the hydrologic component process in surface water and groundwater. The average recharge rate was estimated at approximately 20.8%.

• Journal of Korea Water Resources Association
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• v.57 no.9
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• pp.633-643
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• 2024

Many coastal countries have developed and used a wide range of technologies and policy measures to protect freshwater aquifers and groundwater resources from seawater intrusion, and have established and implemented a foundation to legally and institutionally support them. This study covers coastal states in the eastern United States, the Netheland, India and Japan. The goal of this study is to analyze each country's legal and policy measures for coastal groundwater management. By introducing Jeju Island's groundwater standard level system, we aim to provide a basis for future discussions on groundwater management measures not only in Jeju Island but also in coastal areas of Korea. As a result of the analysis, despite the various contents and aspects of coastal groundwater management based on local issues and characteristics around the world, in order to achieve the common goal of securing a stable amount of groundwater withdrawal and preventing seawater intrusion and to maximize the efficiency of groundwater management, it is understood that attempts are being made to establish optimal management measures, laws, systems, and policies based on several key factors. First, considering the hydrogeological characteristics and status of coastal groundwater, a separate special management system is being established and implemented within the scope of the national groundwater management system. In addition, preventing and maintaining groundwater level decline through limiting the amount of groundwater withdrawal and preventing seawater intrusion are key policy goals and policy tools, and it is suppored by research and development. Finally, tt was found that synergy effects are being sought by using various other policy tools and measures in a complex manner.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.475-486
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• 2005

According to the inference results of formation process of the tectonic lineament, totally four events of subsidence including two events after upheaval of granite body and two events after sedimentation of unconsolidated sedimentary layer formed the macroscopic tensional lineament. The subsidence was occurred by tensional stress oriented ENE-WSW direction and compressional stress oriented NNW-SSE direction. The deeper distribution of tuff and unconsolidated sedimentary layer as much as 70-140m and that of granite as much as 50-500m at Hamdeok and Shinheung than those of the eastern and the western area around Hamdeok and Shinheong is due to the Hamdeok-Pyoseon Graben by three events of differential subsidence from Hamdeok to Pyoseon including Shinheung.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.09a
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• pp.55-71
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• 2005

Jeju Island is mainly composed of basaltic lava flows and subordinate amounts of volcaniclastic sedimentary rocks. Jeju Province operates the monitoring wells for seawater intrusion problems around Jeju Island to evaluate of groundwater resources in coastal area. Various surveys and monitoring have been performed in boreholes, and also conventional geophysical well loggings conducted to identify basalt sequences and assess seawater intrusion problems. Various conventional geophysical well logs, including radioactive logs, electrical log, caliper log, and temperature and conductivity log and heat-pulse flowmeter log were obtained in 29 boreholes. The results of geophysical well loggings for saturated rocks are interesting and consistent. Natural gamma logs are useful in basalt sequences to sedimentary interbeds, unconsolidated U formation, and seoguipo formation with higher natural gamma log regardless of saturated or unsaturated basalts. Neutron logs are very effective to discriminate among individual lava flows, flow breaks, and sedimentary interbeds in saturated formation. In hyalocastite, porosity is high and resistivity is low, and we think that hyalocastite is a major pathway of fluid flow. In trachybasalt, porosity has a wide range and resistivity is high. In sedimentary interbeds, unconsolidated U formation and seoguipo formation, porosity is high and resistivity is low. The temperature logs in eastern area in Jeju are useful to interpret the hydrogeological unit and evaluate seawater intrusion in Suan area.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.1-6
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• 2012

Total Economic Value (TEV) provides a framework to estimate the economic value of water resources including groundwater with multiple applications to natural resource economics and environmental economics. Crucial to the application of economic analysis to natural resources are techniques to value the resources as an economic value that is expressed in monetary terms. On the other hand, the aim of TEV estimation is to determine the economic value of water resources including 'use' with production and recreation and 'non-use' such as existence values. TEV is used to assess the economic value of water resources for the multiple goods, and environmental 'services' that are provided by a water resource and also used to assess options for water use, for example balancing production values provided by water resource use against the cost of resource degradation by that use. The value of TEV can be assessed over time where pollution or unsustainable use may reduce the economic value of an environmental asset. Therefore, values are used to assess options of resource use, sometimes leading to policies on resource conservation or allocation. In conclusion, the application of TEV would be well adjusted over Jeju Island where groundwater resources account for more than 98% water resources and the budget of water demand/supply shows disparity over the Island.